Microsoft has released two updates that optimize the performance of AMD Bulldozer CPUs on Windows 7-based or Windows Server 2008 R2-based computers.

KB2645594(install this first)
The CPU scheduling techniques that are used by Windows 7 and Windows Server 2008 R2 are not optimized for the AMD Bulldozer module architecture. Therefore, multithreaded workloads may not be optimally distributed on computers that have one of these processors installed in a lightly-threaded environment. This may result in decreased system performance for some applications. When this update is installed, the scheduler will be aware that your Bulldozer processor contains dual-core modules. In essence, threads 1-4 now get assigned to their own module first.

KB2646060(should only be installed after KB2645594)
The CPU Power Policies that are used by Windows 7 and Windows Server 2008 R2 are not optimized for the dual core AMD Bulldozer module architecture. This can result in decreased system performance with multithreaded workloads in lightly-threaded environments. When this update is installed, Bulldozer modules will be less likely to achieve the C6 power state. This potentially results in increased power consumption in more lightly-threaded environments.

After reading description of these updates i think it is not so sure what is the problem for real. This is new architecture, very distinctive when we compare it to all previous cpus of both sides: amd and intel. I can say: yes, amd failed by making something innovative and not elaborating it to be as good in performance as customers expected, but it is a bit of microsoft's guilt of not releasing proper updates on time of cpus release date.

I hope amd will elaborate their new architecture and next cpus based upon this will be very powerful and energy-saving if they will i'm almost sure these future cpus will beat up few another generations of intel's cpus.

so they are only 20% slower than the equivalent Intel processor instead of 30

That depends when and where. Recompiled software often runs comparably on SB and BD... in some cases BD can even be faster. That of course doesn't matter much for typical user as he has no means to recompile sources

When the benchmarks arrive, i doubt it can even hit 2% increase in most apps... AMD Claims up to 10% increase not that it is a constant 10% everywhere, as AMD claims:

*Our testing shows that not every application realizes a performance boost. In fact, heavily threaded apps (those designed to use all 8 cores), get little or no uplift from this hotfix – they are already maxing out the processor. In other cases, the uplift averages out to a 1-2 percent uplift. *